Projectile



May 19, 1942. I H. .J. NICHOLS PROJECTILE Filed July 6, 1940 materials,parachutes, etc.

Patented May 19, 1942 UNETE azsam AT EN T raomcms Harry I. Nichols,Binghamt'on, N. Y.

Application July 6, 1940, Serial No. 344,261 2 Claims. (01. 102-26)quence, the former simple classification of the projectiles as to typeshas been greatly extended, and now includes high-capacity, anti--aircraft, anti-tank, gas, incendiary, smoke, illuminating, tracer, andother specialized types. Many of these specialized types demand themaximum internal capacity for the most efllcient utilization of largebursting charges, chemical Also, gun pressures and projectile velocitieshave increased, requiring stronger projectiles to withstand the stressesdue to firing. In short, the evident trends in special projectile designnecessitate optimum design considerations, as well as the extensiveuse-of high-quality steels.

It should benoted here that the trends described above tend to increasethe cost of the individual projectile, both by requiring more expensive,high-quality steels, and by increasing 3 the cost of machining thesehigh-quality steels. The demand for high-quality projectiles intremendous -quantities also tends to create a milltary-economic problemby reason of the danger of depletion of supplies of strategic materials,such as alloys for special steels, cutting tools, machine tools,- etc.In the World War, the French were forced to thicken the walls of certainprojectiles to enable lower grade steels to be used as the supply ofalloy steels was depleted, adversely affecting the supply of munitionsas well as the performance of the projectiles themselves. The copperused for the rotating bands or projectiles is also a strategic materialof prime military importance. Such demands and costs thus becomeimportant factors in preserving the military and economical fronts inthe event of a long major war.

On studying and analyzing the general and particular considerationstouched upon above, I 5 find that important direct and indirecttechnical, military, and economic advantages can be realized by aradical change and improvement in the form and method of constructingand assembling the rotating bands of projectiles.

i5. a nexed drawings and The rotating band not only forms an essentialfunctional part of all projectiles for rifled cannon, but it alsoafiects the strength of the projectile, the ballistics of theprojectile, and the life, serviceable condition, and accuracy of the gunin which the projectile is fired. It is a reco nized fact of the historyof ordnance that the'rotating band of projectiles in its present form isthe result of along revolutionary process.

It is accordingly one of the principal objects of this .invention toimprove the strength and performance, to facilitate the manufacture, andto reduce the cost of small calibre projectiles by providing a, radicaldeparture in the form of,

and the method of constructing and assembling,

the rotating band therefor.

A further object is to meet in'a highly eflicient, reliable, andpractical manner the general and special requirements for the massproductlon of small calibre projectiles for use in rifled guns.

Another object is to improve the strength of the projectile as a wholeby eliminating the necessity of cutting a band score in the sidewalls ofthe projectile.

- Anotherobject is tion of a rotating band on a projectile whicheliminates the expense of cutting a groove,-band score, or undercut onthe projectile body.

' Another object is to provide'a rotating band on a projectile whicheliminates the need for hammering, Dressing, .or squeezing the band intoa groove or score in the projectile, which method yet assures agas-tight connectionbetween the rotating band and the projectile.

Another object is to greatly reduce the quantity of copper needed toform the rotatingband of a tpirojectile, as compared to prior universalprac- Another object is to improve the-rotating band of a projectilewith respect to its wearing efiect on the riding of the gun.

Another object is to improve projectiles by providing a rotating bandcapable of forming a corrosion preventing film on the walls of a gunbore when such projectiles are fired therein.

Another object is to provide a form of rotating Other objects will inpart be obvious from the to provide for the construcin part hereinafterindior conical head ll.

cated in connection with the following analysis of the invention.

This invention accordingly consists in the features and forms ofconstruction, combination of parts, and in methods and processes forobtaining unique advantages in the manufacture of projectiles as well asin the projectiles themselves, all as more completely outlined herein.

To enable others skilled in the art fully to comprehend the underlyingfeatures of this invention, that they may embody the same in variousforms and apply the same to various sizes and types of projectiles ascontemplated by the invention, a drawing depicting preferred embodimentsof the invention form a part of this disclosure, and in such drawinglikecharacters of reference denote corresponding parts thruout the severalviews, in which:

Fig. 1 shows in part section a typical projectile according to theinvention and a rotating band applied thereto in accordance with theteaching of the invention.

Fig. 2 similarly shows another embodiment of the invention providing acombination rotating and anti-fouling band applied to a typical form ofprojectile, all in accordance with the teaching of the invention.

Referring now to the drawing, and particularly to Fig. 1, it is wellknown that modern projectiles for rifled guns are typically of the samegeneral form, having a cylindrical body III with an ogival The head ilmay be integral with the body ill, or it may be a separate part, or anassembly of parts- In very small projectiles, a point fuse may serve asa head II, as indicated by the dotted lines of 'the drawing. The forwardpart of the body I is usually turned or ground to make an accuratecylindrical hearing surface for the front part of the projectile.

- This surface is called the bourrelet and is indi .cated at l2. Thebody is closed at the base l3,

either by a base plug I l, as in Fig. 1, or by an integrally formed basearch H as in Fig. 2.

The body I0 is also fitted with a driving or rotating band 20. Inconventional practice, it is usually located near the base l3 in anannular groove (not shown) machined in and around the body l0. One ormore rotating bands may be used, located either closely spaced near thebase, or near the base and at the bourrelet. In addi tion, some modernprojectiles are fitted with a' creases rapidly as the calibre of theprojectile diminishes, and may exceed 40,000 times the weight of theparts forward of a given transverse section in the case of projectilesof small calibre. In fact, in the design of high-capacity projectile Ibodies, such as shrapnel shells, (Fig. 2) the separate decoppering oranti-fouling ring in the form of a narrow ring of special non-ferrousmetal or alloy assembled to the projectile just rearwardly of therotating band, or in a groove in the rotating band.

The rotating band 20 performs the functions of centering the projectileaccurately and snugly in the bore of the gun, of sealing the projectilein the bore of the gun on firing to prevent the escape of propellantpowder gases, and of engaging the rifiing of the gun to impart rotationto the projectile to stabilize the same in flight. In addition to theprimary functions of the band itself,

in typical projectiles of the prior art, the effect of cutting thegroove for the band, calledthe band-score, into the wallof theprojectile body "requires particular consideration from the stand--point of reducing the ability of the body to withstand the firingforces, and the shock of impact in the case of armor piercingprojectiles. view of the importance of these functions, and the need ofprotecting the bore of the gun against corrosion, wear and damage duringthe firing of strength reduction of the side wall due to the band-scorenecessitates the use. of the highest quality alloy steels to withstandthe firing forces of modern high'power guns without danger of the bodyupsetting or collapsing in the bore. At extremely low'temperatures,there is particular danger of damaging or destroying guns due tobreaking up of projectiles in the gun because of embrittlement of theprojectiles at such temperatures.

The cost of the rotating band itself, the cost of machining theband-score in the body, and the cost of assembling the band. to theprojectile comprise a substantial part of the-cost of the completeprojectile, particularly in the case of small calibre projectiles.Rotating bands are usually made of copper, or a high-copper alloy suchas bronze or cupro-nickel, which must be of high quality andexceptionally uniform in physical properties. According to prior art,the bands are generally made from rings out from annealed, seamlessdrawn tube of the right size, thickness, and material. The ring isslipped over the projectile to the band groove, and is then hammered orsqueezed into place by powerful machinery, not shown. This step of themanufacturing process involves expensive machines or else laboriousmanual operations, and also presents technical difliculties. The bandafter being squeezed into place may be strained and loosen up laterunder further thermal or mechanical strains. Or, due to unequal workhardening during the hammering or squeezing, hard spots may be createdwhich damage the rifiing of the gun at firing. Further, the extensivedeformation to which the band is subjected during assembly has in thepast closely limited the choice of suitable metals or alloys, since fewmaterials will permit of such extensive deformation as occurs inshrinking a rotating band into place without excessive work-hardening.

In order to prevent the band slipping on the projectile at firing, andto prevent leakage of powder gases between the band and the projectile,special constructions of the band score have been found necessary. Onemode of construction widely employed is to under-cut the edges grooveare undercut, and pointed ridges in the bottom of the groove are alsoemployed. It will be appreciated'that'while this third mode ofconstruction is quite thorough, it is also very expensive. 1

Referring now again to Fig. 1, according to the methods according towell known practices can be followed to form the rotating band in placeon' the projectilebody, the preferred method is that technically knownas electro-forming. The following steps (which permit of some vari=ation in order) are preferred: (1) The body itself and the site on thebody I!) intended to receive the band isformed or machined to therequired size; (2) the body is protected or insulated in such manner asnot to receive an elec-' tro-deposit at the time the band is beingdeposited; ,(3) the site is cleaned and prepared to receive anelctro-deposit thereon in such manner that the deposit will adherestrongly to the body; (4) the body is mounted as a cathode in anelectro-plating bath; and by means of electric-current, (5) a metaldeposit of the required nature, quality, and thickness is formed as acontinuous integral homogeneous ring around the body to the full heightof the hand. Thereafter, (6) the perimeter of the band is finishmachined to the size and form required. As in the case of presentpractice, all heat treating processes should ally result in loosening ofthe band and hence failure to perform the desired functions. A furtheranti-fouling metals.

be completed before the band is applied. Otherwise, heat strains orannealing effects might cause the band to loosen from the projectile.

Variations in the order of steps recited above are clearly permissible.For example, the entire projectile body may be coated with an imperviouscoating such as asphaltum varnish, 'or a japan or lacquer, so as toprevent electro-deposits thereon, and thereafter such coating may beremoved at the band site when the body is being machinedor ground tosize. After suitable preparation, the band is electro-formed in place,

' Regardlem of the order'of steps and the process employed, theinvention comprehends preparing the site of the rotating band fordepositing metal thereon, insulating other surfaces of the projectileagainst such deposition, depositing anon-feraas "Electro-depcsition ofMetals" by Langbein;

Principles of Electro-plating and Electra-forming by Blum and Hogaboom;and "Modern Elecr -pla ing y 08 3; i 3 However, with respect to thepresent invention,

it may be pointed out that complete adhesion or bonding between theprojectile and electroformed ring is necessary, since because ofdissimilar metals being used for the body and band,

Y ing point metallic film as firing progresses. This practical requiremet is that the forming process be closely controlled to assure uniformityin hardness of the deposited metal.

The material deposited to form the rotating band may be a single metalas, for example, pure copper; or a non-ferrous alloy of copper and adissimilar metal haying anti-fouling characteristics, such as zinc orcadmium; or a ring of copper may be surfaced with a deposit of suchdissimilar Because of the facility and speed with which it can beelectroformed, copper is the preferred material for the rotating bandper se. But to obtain anti-fouling jeifects alloys of, or combinationsof dissimilar metals, are requisite. Copper is the preferred materialfor the rotating band because it can be readily electroplated to buildup relatively thick deposits quickly or uniformly.- Any suitable knowncommercial plating process may be used.

The anti-fouling addition to the rotating band is preferably asuperposed layer of metal or alloy electroplated over the copperrotating band after the latter has been machined to size. The term"anti-fouling is intended to cover the prevention or amelioration ofvarious adverse effects of the propellant and projectile on the walls ofthe gun bore arising from repeated firing. These effects are: corrosiveaction on the gun bore due to chemical action of the propellantingredients, gases, and residual compounds; and metal deposits on thegun bore, mainly from the scouring action.

between the gun barrel and the rotating band of the projectile. Onrepeated firing such metal deposits may, and usually do, accumulate inthe bore of the gun tending to impair the accuracy of fire, and unlessremoved they may cause explosion of the gun or projectile. l

The anti-fouling layer on the. rotating band 1 causes the gun barrel tobe coated with a low meltfilm is selflimiting in thickness and inhibitscorrosion and copperlng. If ordinarly projectiles having the usual typesof copper r'otating bands are fired in the same gun, interspersingprojectiles fitted with rotating bands embodying this invention duringfiring will remove the copper deposits.

formed by such ordinary projectiles. This is an example of de-coppering"action. Referring now to Fig. 2, two featuresare particularly to benoted. The after part of a shrapnel shell of conventional type is shown,witha rotating band according to the invention applied thereto. Inshrapnel, it is desired to obtain the maximum capacity within a shell ofgiven size calibre. The strength of the projectile 'side wall at thereduced section when a band score'of OOH-e ventional type is cut thereinthus becomes'the limiting factor in the design of shrapnel. It is clearthat the present invention provides the advantage of enabling the use ofa lower-quality of thermal changes and/or electrolysis may eventusteelfor the same thickness of sidewall; provides larger capacity bypermitting the use of a thinner side wall while retaining the samequality of steel for the projectile body, provides greater strength ofside wall for the same material and thickness. or a combinationof theseadvantagesin part. 1

Referring "now to the rotating band 20-4: 6r

Fig. 2, the construction there shown represents a laminatedor'layer-deposited band in which the layer 20 next to the body may be,for example, pure copper as previously described; while the outer layer,indicated by 2|, is a special anti-- fouling layer, as for example,cadmium or zinc: or alloys containing a high proportion of these metals,as for example an alloy of copper 85-95% zinc -15%- with or without afew percent of cadmium.

In some cases, it may be found desirable to rotate the projectile whiledepositing the metal of the rotating band. This is especially desirablewhere the maximum speed in the plating process is desired, and can beadvantageously applied to large scale practice of the present invention.

Without further description or analysis, it will readily be perceivedthat the present invention provides such substantial direct and indirectadvantages in the art of construction of projectiles as fairly to mark arevolutionary step in advance. These advantages encompass materialadvantages in the rotating band per se, as for example, improvedmechanical properties such as more uniform hardness, and a wider rangein the choice of materials, including alloys having anti-copperingproperties; improvement in the functions of the rotating band, as forexample stronger adherence to the projectile, stronger grip on therifiing, and more certain sealing of gun gases; advantages in the designand performance of the projectile, as for example thinner side-walls andlarger capacity, greater strength to resist firing stresses, and moreuniform flight; and advantages tothe gun, such as diminished wear due tothe elimination of hard spots in the bands thus improving the life ofthe rifling, and by facilitating the use of anticoppering orde-coppering alloys thereby reducing erosion, preserving the accuracy ofthe gun, and

promoting uniformity in the interior and exterior ballistics.

In addition; the indirect advantages include lower cost of the rotatingband; saving in the cost and operation of handing machinery; less copperrequired; less alloy steel required; less cuttin tools and cuttingmachines required; etc. In the aggregate, these are substantialadvantages, and their attainment by the simple means of the inventionrepresents a distinct advance in the art.

I claim:

' 1. An article of manufacture comprising a ferrous projectile body forrifled cannon having a cylindrical body portionof substantially uniformdiameter behind the nose and free from rotating band grooves or landsand having a deposited bonded rotating band in the form of an integralhomogeneous ring built up in its entirety directly on the outercylindrical surface of said body portion to full band height from atleast one of the soft non-ferrous metals.

2. An article of manufacture comprising a projectile for rifled cannonhaving a cylindrical ferv rous body portion of substantially uniformdiameter behind the nose and free from rotating band grooves or landsand having a deposited bonded anti-fouling rotating band in integralhomogeneous ring form built up in its entirety directly on the outercylindrical surface of said body portion to full band height, the bandcomprising copper and at least one anti-fouling metal selected from thegroup consisting of zinc and cadmium.

HARPY J. NICHOLS.

